The number of matings obtained by a male is likely to be a major component of his lifetime fitness. Males that depend on finding mates before their competitors must allocate resources to this effort, potentially at the expense of their reproductive rate. Male crab spiders Misumena vatia (Clerck 1757) often occur at low densities and experience considerable difficulty in finding females. This constraint might select for their cursorial body form and high movement rates at the expense of their reproductive rate. Male M. vatia will not mate more than once in rapid succession and typically no more than once every other day, although they are capable of several matings over their lifetime. Males may rarely encounter virgin females more often than once every other day and thus would experience little loss of fitness from an inability to mate in rapid order.